hey guys i am going to make a 427 ls1 motor this winter in my 02 ws6. but i was wondering if you could resleeve the motor and make it a 455. like 427 is really a chevy motor ya know and pontiac had the 455. Now i see that lunati makes a 447 rotating assembly for the ls1, so is there a way to get the extra 8 cubes outa the motor to make it a 455? thanks guys.
Jon

 

MTI put one in a GTO but it was an MID block.......

 

technically yes, but probably not worth the money.
https://ls1tech.com/forums/generation-iv-internal-engine/351591-darton-large-bore-ls2-dry-sleeve-here.html

that is the block you would need, bored to 4.155''
and like a 4.2'' stroke to get to 455''

 

Lunati does make a 454 kit. You may just have to round up one inch, just like the 382, 396 guys do

 

didnt texas speed do it by offset grinding the crank?

 

i didnt know lunati made a 454 kit, i guess the place i was looking only had up to 447. i will have to look into it, thanks guys.
Jon

 

Yeah, I don't think its listed on their website, but they do offer a 4.25" LS1 crank.

At the time I was debating between 427 and 396 (5) , I was told I could also go 454.

 

4.2" Bore with the new MID Sleeves and a 4.125" Crank will give you 457. That will make more power than a 455 with a 4.155" bore and 4.2" Crank because of the extra breathing capabilities of the increased bore, not to mention it will rev easier.

Better put a carb type manifold on it and a rectangle port LS7/C5R style head, though, to make a noticeable power improvement over the 427s on something with that many cubes. LSX90 intake and ported LS6 or AFR225 heads are simply too small for an engine that big.

 

or put a 4.25 crank on that bad boy and you have a 471

 

MTI used a 4.160 (max bore) Darton MID wetsleeve kit and a custom 4.185 stroke

 

Would boring an LS1 block that big make it very weak?

 

Can't bore the aluminum LS1/6 block because it has iron ductile sleeves in it. The Modular Integrated Deck (MID) of Darton does strengthen it a bit, but just because the sleeve is bulletproof doesnt mean the thin aluminum block behind the thing MID sleeve won't warp on itself and crack somewhere else.

You can safely bore the LQ4/9 block .030" over and sometimes as high as .060" with a sonic test of the block.

The C5R block can be bored to 4.130".

 

no, the iron liners are only about .060 thick.

 

I think you're mistaken. That would be a HUGE crank! Chevy big block style. There's a 4.125" crank and a 4.185" crank and I think Lunati offers them both. The easiest way to get a 455 woud be the 4.160" bore block(either gen III or gen IV but gen III is going to be wet-sleeved=$$$) and a Lunati 4.185" crank. Another alternative would be a 4.200" bore gen III resleeved block and an Eagle 4.100" crank which would give you 454.4ci which would definitely pass as a 455 in my book. If not, after a year or so when all that friction wears on your cylinder walls, you'll have your .1cubic inch.

 

There is a difference between a 382 and a 383. The 382 is a 4.000" crank on a factory bore(3.898") but a 383 is a 4.00" crank on a 3.903" bore.

 

The Pontiac 428 was actually 427 and had the exact same bore & stroke as the new LS7 - 4.125 x 4.00. So go 427 and call it 428! You could also go 421 with less bore for another good classic Pontiac number.

 

Pardon me for saying so, but to choose a stroke based on just the fact that Pontiac used to have some is, well, ...******* stupid

Sorry, my apologies, I couldn't restrain myself.

 

I agree, are you spending money on the motor to make the car faster, are or you spending the money on the motor so you can run a special badge.

 

to anyone who wants to know how to get a certain engine size in cubic inches... here is the formula to find out bore and stroke combos and what they would equal...

BORE X BORE X STROKE X .7854 X 8 (or amount of cylinders for anything other than a v-8).

and as far as just wanting to max out an enginge's capability just so you can say you have a 455 is kinda lame to me. but that's just my honest opinioin.

 

for example... 4.125 x 4.125 x 4 x .7854 x 8 = 427.65 cubic inches. C5-r / LS-7 bore and stroke combo.